API Clients

An API Client is a software application that allows developers to create, save, and send HTTP requests to an API and view the response. It is the workbench of the API developer.

We can categorize these clients into three generations:

Integrated Platforms: Cloud-connected powerhouses (Postman, Apidog, Hopscotch).

Local-First / Lightweight: Fast, offline tools focused on privacy (Bruno, Yaak, Insomnia).

IDE Extensions: Built directly into VS Code (Thunder Client).

1. Integrated Platforms

Tools that do more than just send requests—they handle Mocking, Testing, and Documentation.

Apidog

Official Website: https://apidog.com/

Screenshot:

Apidog's unifying interface: Design (Specs), Debug (Run), and Testing in one window.

The All-in-One: Apidog markets itself as Postman + Swagger + Mock + JMeter.

Best For: Teams who want to stop manually syncing their docs and mocks with their code.

Key Feature: Design-First Workflow. You define the API structure, and it automatically generates the documentation and mock server for you.

Pricing: Generous Free Tier (unlimited team members), Pro plan for advanced governance.

Postman

Official Website: https://www.postman.com/

Screenshot:

The Industry Standard: The most famous tool with a massive community.

Key Feature: Postbot (AI) that helps generate tests and fix errors.

Cons: Has become "heavy" and slow over the years. Recent changes to remove "Offline Scratchpad" forced users into the cloud, sparking privacy concerns.

Hopscotch

Official Website: https://hopscotch.io/

Screenshot:

Hopscotch's lightweight, browser-based interface.

Open Source Postman: Originally "Postwoman", it runs entirely in the browser (PWA).

Key Feature: Lightweight. It loads instantly and doesn't require a heavy desktop install.

Cons: Web-based CORS issues can sometimes be tricky without their browser extension.

2. Local-First & Lightweight Clients

These tools emerged as a reaction to Postman becoming too "cloud-heavy". They focus on Speed, Privacy, and Git Integration.

Bruno

Official Website: https://www.usebruno.com/

Screenshot:

Bruno stores collections as plain files, visible in the sidebar.

The "Git-Native" Revolution: Bruno stores your collections as plain text files (.bru) directly in your project folder alongside your source code.

No Cloud Sync: You sync via git push / git pull. No third-party servers holding your secrets.

Pricing: Completely Open Source (MIT). Golden Edition for advanced support.

Yaak

Official Website: https://yaak.app/

Screenshot:

Yaak's clean, Rust-powered interface.

The Beautiful Minimalist: Built in Rust/Tauri. It is incredibly fast (launch time < 1s).

Key Feature: gRPC & GraphQL are first-class citizens, not afterthoughts.

Philosophy: "Privacy First". No telemetry, no accounts.

Insomnia

Official Website: https://insomnia.rest/

The Classic Alternative: Now owned by Kong.

Key Feature: Kong Gateway Integration. If you use Kong, Insomnia allows you to deploy routes directly.

Note: Like Postman, Insomnia largely pivoted to the cloud in version 8.0, though they re-introduced some local capabilities after community feedback.

3. IDE Extensions

Thunder Client

Link: VS Code Marketplace

Screenshot:

Thunder Client running directly inside a VS Code tab.

The Convenience King: A full GUI client inside VS Code.

Best For: Solo devs who hate Alt-Tab switching.

Comprehensive Comparison

Tool	Type	Key Strength	Best For	Rating
Apidog	Platform	Design + Mock + Test	Full Lifecycle Teams	⭐⭐⭐⭐⭐
Bruno	Local	Git / File-Based	Privacy / DevOps	⭐⭐⭐⭐⭐
Postman	Platform	Massive Ecosystem	Enterprise QA	⭐⭐⭐⭐
Yaak	Local	Speed (Rust)	Minimalists	⭐⭐⭐⭐
Hopscotch	Web	Browser-Based	Quick Web Testing	⭐⭐⭐⭐
Insomnia	Local/Cloud	Kong Integration	Gateway Users	⭐⭐⭐
Thunder Client	Extension	Context Switching	VS Code Users	⭐⭐⭐

Recommendation

For Teams: Use Apidog to unify your Design, Docs, and Testing in one place.

For Hackers/DevOps: Use Bruno. Storing API requests in your Git repo is a game changer for CI/CD and versioning.

For Speed: Use Yaak or Thunder Client for quick, one-off checks.

Key Takeaways

Integrated Platforms (Apidog, Postman) are best for teams needing full lifecycle management.

Local-First Clients (Bruno, Yaak) are gaining popularity for their speed and privacy.

IDE Extensions keep you in the flow but lack advanced features.

Next Step: Sometimes you don't need a UI at all. Let's master the command line in Command Line Tools (cURL, HTTPie).

1. Integrated Platforms#

Apidog#

Postman#

Hopscotch#

2. Local-First & Lightweight Clients#

Bruno#

Yaak#

Insomnia#

3. IDE Extensions#

Thunder Client#

Comprehensive Comparison#

Recommendation#

Key Takeaways#